The rate at which energy is expended, or at which work is performed. Its symbol is P, its abbreviation is pwr, and it is usually expressed in watts, or some multiple of watts, such as megawatts. When dealing specifically with the rate at which electric energy is utilized in a DC circuit or system, it is equal to the potential difference, expressed in volts, multiplied by the current, expressed in amperes. In an AC circuit or system, true power is the rate at which work is performed or energy is transferred, apparent power is the product of the RMS current and the RMS voltage, while reactive power is the power in an ACcircuit which cannot perform work. Also called electric power (1).

A number indicating the exponent to which another number, the base, is raised. For example, in 28, the 8 is the power, and the 2 is the base. Also called exponent.

The product obtained when multiplying a given number by a given power (3). For instance, in 28,2 is raised to the 8th power, which results in 256.

The multiplication of a given number or value by another, to express a multiple of a given standard or reference. For instance, 256X over-sampling, or a 64x DVD drive.

A measure of the ability of a lens, or optical system, to magnify an image or object.